The present invention relates generally to the field of fans and, in particular, to modular fan units for chassis.
Chassis are often used to contain circuit cards, such as circuit cards of telecommunications systems. In telecommunications applications, several chassis for containing circuit cards are, for example, stacked one above the other and are secured in a rack located in a central office or other location. Many of these circuit cards dissipate heat that if not removed from the cards and subsequently from the chassis, can cause the circuit cards to fail.
Many chassis are passively cooled chassis, e.g., heat is removed from the cards and chassis by a natural convection airflow induced by a temperature difference between heated air within the chassis and cooler air outside of the chassis. In one application, outside air is drawn into the chassis through openings at the bottom of the chassis. The air flows generally vertically through the chassis and over the cards so that heat is transferred from the cards to the air, thereby heating the air. The air exits the chassis through openings in the top of the chassis. However, in some stacked arrangements, the heated air flows from the top of one chassis into a chassis above, resulting in reduced heat transfer from the cards of the chassis above. Consequently, baffles are sometimes located atop passively cooled chassis for directing the air flow generally horizontally through the back of one chassis so that the heated air does not flow into a chassis above.
However, the natural convection airflow through some of these passively cooled chassis with baffles does not transfer enough heat from the circuit cards and chassis. Therefore, the circuit cards can overheat and fail. As a result, passively cooled chassis are sometimes replaced by actively cooled chassis, e.g., having fans or other active cooling devices for forcing air through the chassis. However, because many actively cooled chassis include integral active cooling devices, replacement of passively cooled chassis with actively cooled chassis often requires the purchase or fabrication of actively cooled chassis, which is not always cost effective. Moreover, there is not always sufficient space in a rack for a chassis having a fan, so the number of chassis within the rack has to be reduced, which is not always cost effective when renting space within a central office. Replacing passively cooled chassis with actively cooled chassis usually requires the removal of the passively cooled chassis and installation of the actively cooled chassis, which is not always cost effective from a labor standpoint and can result in a disruption of services.
For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for equipping existing passively cooled chassis with active cooling devices.
The above-mentioned problems with replacing passively cooled chassis with actively cooled chassis and other problems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification.
One embodiment provides a modular fan unit having a frame receivable within a baffle of a chassis for containing electronic components. Each of a pair of brackets is connected to an end of the frame to form a slot for receiving a wall of the baffle. Moreover, each of the pair of brackets is respectively attachable to a pair of walls of a rack containing the chassis. A fan is attached to the frame so as to align with an aperture located between the pair of brackets and passing through the frame. A controller is attached to the frame and is electrically connected to the fan.
Another embodiment provides a method for retrofitting a passively cooled chassis for active cooling. The method includes inserting a modular fan unit into a baffle for exhausting fluid from a rear of the chassis so that an aperture of the modular fan unit forms an outlet of the baffle. A fan of the modular fan unit aligns with the aperture and is located within the baffle. Respectively receiving a pair of opposing walls of the baffle within a pair of slots of the modular fan unit is also included in the method. The method includes securing a pair of brackets disposed at opposite ends of the modular fan unit to a pair of walls of a rack containing the chassis. The chassis is diposed between the pair of walls.
Other embodiments are described and claimed.